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-rw-r--r--doc/log.txt6
-rw-r--r--src/block/idea_sse2/idea_sse2.cpp6
-rw-r--r--src/utils/asm_x86_32/info.txt1
3 files changed, 7 insertions, 6 deletions
diff --git a/doc/log.txt b/doc/log.txt
index 988e4d71d..012a37041 100644
--- a/doc/log.txt
+++ b/doc/log.txt
@@ -15,6 +15,12 @@ Version 1.9.18, Not Yet Released
* Add support for compiling SSL using Visual C++ 2010's TR1
implementation.
+* The SSE2 implementation of IDEA did not work correctly when compiled
+ by Clang, because the trick it used to emulate a 16 bit unsigned
+ compare in SSE (which doesn't contain one natively) relied on signed
+ overflow working in the 'usual' way. A different method that doesn't
+ rely on signed overflow is now used.
+
* Fix a bug under Visual C++ 2010 which would cause ``hex_encode`` to
crash if given a zero-sized input to encode.
diff --git a/src/block/idea_sse2/idea_sse2.cpp b/src/block/idea_sse2/idea_sse2.cpp
index b92f51ac3..81b0fd9c1 100644
--- a/src/block/idea_sse2/idea_sse2.cpp
+++ b/src/block/idea_sse2/idea_sse2.cpp
@@ -16,7 +16,6 @@ inline __m128i mul(__m128i X, u16bit K_16)
{
const __m128i zeros = _mm_set1_epi16(0);
const __m128i ones = _mm_set1_epi16(1);
- const __m128i high_bit = _mm_set1_epi16(-32767); // 0x8000
const __m128i K = _mm_set1_epi16(K_16);
@@ -29,10 +28,7 @@ inline __m128i mul(__m128i X, u16bit K_16)
__m128i T = _mm_sub_epi16(mul_lo, mul_hi);
// Unsigned compare; cmp = 1 if mul_lo < mul_hi else 0
- const __m128i cmp = _mm_srli_epi16(_mm_cmpgt_epi16(
- _mm_add_epi16(mul_hi, high_bit),
- _mm_add_epi16(mul_lo, high_bit)),
- 15);
+ const __m128i cmp = _mm_min_epu8(ones, _mm_subs_epu16(mul_hi, mul_lo));
T = _mm_add_epi16(T, cmp);
diff --git a/src/utils/asm_x86_32/info.txt b/src/utils/asm_x86_32/info.txt
index 8534d9aef..21244968f 100644
--- a/src/utils/asm_x86_32/info.txt
+++ b/src/utils/asm_x86_32/info.txt
@@ -19,7 +19,6 @@ solaris
</os>
<cc>
-clang
gcc
icc
</cc>